Formation of BaTiO3 from barium oxalate and TiO2

Barium titanate powder has been prepared via a semi-oxalate method that uses barium oxalate and TiO2 precursors, instead of titanyl oxalate. Barium oxalate was precipitated from nitrate solution onto the surface of TiO2 powders. Crystallization of BaTiO3 from the precursors was investigated by TGA, DTA and XRD analysis. It is evident that an intermediate barium oxycarbonate along with BaCO3, forms between 450-500degreesC and that decomposes to BaCO3 again at high temperature. Decomposition of BaCO3 occurs at much lower temperature, from 600degreesC onwards, due to the presence of TiO2. The precursor completely transforms into BaTiO3 at 900degreesC. Nanometer size BaTiO3 crystallites are produced during this synthesis due to the lower calcination temperature. The crystalline morphology of BaTiO3 is controlled mainly by the morphology of BaCO3, which formed in the intermediate stage.